Stories set in the future are often judged, as time passes, on whether they come true or not. “Where are our flying cars?” became a plaintive cry of disappointment as the millennium arrived, reflecting the prevailing mood that science and technology had failed to live up to the most fanciful promises of early 20th-century science fiction.

But the task of science fiction is not to predict the future. Rather, it contemplates possible futures. Writers may find the future appealing precisely because it can’t be known, a black box where “anything at all can be said to happen without fear of contradiction from a native,” says the renowned novelist and poet Ursula K. Le Guin. “The future is…